Biophysical methods have been developed for preparing simplified mixed of native antigens in filtrates of M. tuberculosis cultures, from which resolution of components can be made. The methods include recognition and removal of the less skin-reactive molecules among antigens which exhibit marked molecular heterogeneity. It is now possible to handle materials of high molecular weight, proteins as well as carbohydrates. We propose to attempt direct isolation of up to seven antigens and, as successful, to prepare monospecific precipitating, diagnostic antisera.